1. Field of the invention
The present invention relates, in general, to a high dielectric ceramic composition and, more particularly, to a high dielectric ceramic composition which is superior in temperature properties with a low loss factor and can be sintered at low temperatures.
2. Description of Prior Art
Generally, a laminated ceramic capacitor is prepared by molding a dielectric ceramic raw material powder into a green sheet, printing on the green sheet a conductive paste comprised of a precious metal such as platinum or palladium, laminating a plurality of such green sheets under pressure, and sintering the lamination at 1,300.about.1,400.degree. C. The precious metal, such as platinum or palladium, used as an internal electrode, however, is very expensive, causing an increase in the production cost of such laminated ceramic condensers.
In order to produce a laminated ceramic condenser at a reduced cost, there were suggested Pb-based, low temperature-sintered dielectrics whose internal electrodes were made of a high content of Ag. These dielectrics can be sintered at low temperatures, but suffer from a disadvantage of having dielectric loss factors as high as 3.about.6%. The conventional dielectrics can be found in many reports (for example, T. R. Shrout and A. Halliyal, "Preparation of Lead-based Ferroelectric Relaxors for Capacitors", Am. Ceram. Soc. Bull., 66[4], 704 (1987); and M. T. Lanagan, N, Yang, D. C. Dube, and S. J. Jang, "Dielectric Behavior of the Relaxor Pb[Mg.sub.1/3 Nb.sub.2/3 ]O.sub.3 -PbTiO.sub.3 Solid-Solution System in the Microwave Region", J. Am. Ceram. Soc., 72[3], 481-83 (1989)).